Thousands of samples of ‘legal highs’ were seized in a police raid at a newsagents in Bradford city centre.

Plain-clothed and uniformed officers arrived quietly at Barkers in Sunbridge Road to execute a warrant.

They forced the closure of the shop and spent about five hours searching the premises on Saturday, seizing various substances and some equipment that officers believe could be used to produce controlled drugs.

Detective Constable Jamie Hudson, who led the operation, said shop owner Pervez Abbas and his son were present during the search. He added that no-one had been arrested.

The raid was part of an ongoing police campaign to tackle the harm caused by the so-called ‘legal highs’ – otherwise known as psychoactive substances.

Officers, alongside a representative of West Yorkshire Trading Standards executed the warrant under the Misuse of Drugs Act.

The substances they seized will undergo forensic testing to establish whether any of their ingredients are controlled by existing legislation or subject to temporary bans. If any test results come back positive, police will look to bring court proceedings.

Detective Chief Superintendent Dave Knopwood, head of Protective Services (Crime), a unit which had officers in the raid, said: “This latest operational activity demonstrates our ongoing commitment to being innovative in the way we target the trade in these substances.

“We remain very concerned that so-called ‘legal highs’ are being sold openly in our high streets, particularly given that this can make young people think they are something that they can take without risk.

“Nationally, we are seeing an increase in deaths and hospital admissions linked to the use of these substances and locally we have seen similar cases. The trade is largely unregulated and tends to operate on the fringes of the law.”

The initiative started in Leeds in December 2012 following concerns that psychoactive substances, which are manufactured as chemical substitutes for illegal drugs such as cannabis, cocaine and ecstasy, are being sold openly in the city centre and increasing evidence of them being linked to the deaths and serious illness of young people taking them.

The campaign includes the distribution of leaflets across the city alongside a programme of awareness-raising visits to schools, colleges and universities.